I hate to be "that guy", but there is one facet of this I did NOT see mentioned above.......
I usually approach projects just from the the technical aspect of "How would I do it", however with anything medical-related a first better question is "Should I do it?"
What if the seal leaks?
What is the IV tube(s) are restricted?
Special precautions may be required to protect life and cover yourself from legal action.
I would expect a medical devices manufacturers to have engineers with big, expensive training and big, expensive insurance for this task.
Also, there must be hundreds of specifications that must be met, both designed to and then tested to.
If this is just a "proof of concept" or "mechanical prototype" perhaps there is no real risk......but if any of it could ever be used to actually treat people then it should be re-designed by the professionals.
-brino